Vesicoureteral reflux (VUR) is the abnormal condition of urine backing from the bladder to the kidney. This disease can result in kidney infections, scarring and ultimately renal failure if not diagnosed and treated in a timely manner. Population studies have demonstrated that VUR is an autosomal dominant inherited condition that ma;y affect one to two percent of children at birth. If one child in a family has been diagnosed with VUR, there is a forty percent risk that each of their siblings will be affected. The long term goals of this project are to determine the chromosomal location of the gene responsible for VUR and to isolate the gene for study. The specific aims of the incumbent proposal are to 1) collect blood specimens form families affected with VUR for gene mapping experiments; 2) extract DNA from the blood samples; and 3) to begin gene localization studies. Gene linkage analysis will be accomplished using amplification of standard genetic markers.